Thread: program reads file and prints runs of the same numbers in the form (number of times * number)

When using a Scanner object, there should always be a symmetry if you will between your call to hasNextXXX() and the call to nextXXX(). So if you are call while (myScanner.hasNextFoo()) { inside of that loop there should only be one call to extract information out with the Scanner and it should be trying to extract the same type of information that the hasNext checked, here the fake method myScanner.nextFoo().

In your code above you check for filescan.hasNext(), which checks the scanner for *any* type token. If you do that, then inside of the loop there needs to be only *one* call to next(). If you want to check for and extract ints, then you should use while (filescan.hasNextInt()), and then call filescan.nextInt() only *once* inside of the block.

ok that makes sense, but then how would i go about assigning the next number of a sequence if i cant call .nextInt again?

You store it in a variable that has been declared before the loop.

Please edit your post and change your [highlight] tags (where'd you get that?) to the proper [code=java] [/code] tags.

Again, call filescan.nextInt() just *once* inside of the while loop. If this were my code, I'd call the method once and put it into an int variable, and then I could use the int held in the variable as many times as I want.

Better for you to test your code yourself. Does the code compile? Does the code work? Does it throw exceptions? Also, please don't double-post your questions as that's not playing fair by the forum rules.

oh yeah I did, and am still working on it, i was just trying to get a visual layout of what you were saying

my input file is ten 20s, five 50s, five 60s, one 20, five 30s, and a 0 in a row
but my output is
(1 * 50)
(1 * 60)
(1 * 20)
(1 * 30)
(0)

ive read over my code multiple times and still dont know why im getting incorrect results,
maybe im just missing a simple mistake, but
any suggestions would be greatly appreciated

import java.util.*;
import java.io.*;
 
public class Proj57015 {
 
	public static void main (String [] args) throws FileNotFoundException{
 
		String filename = args[0];
		System.out.println("Data File: " + filename);
		System.out.println("");
		Scanner filescan = new Scanner(new File(filename));
 
		int num1 = filescan.nextInt(), num2;
		int count = 1;
 
		while (filescan.hasNextInt()){
			num2 = filescan.nextInt();
			if(num1 == num2)
				count++;
			else if(num2 == 0){
				System.out.println("(0)");
				System.exit(0);
			}
			else if(num1 != num2){
				count = 1;
				num1 = num2;
				System.out.println("(" + count + "*" + num1 + ")");
			}
		}
	}
}

It looks like that code will print something almost every time through the loop.
I would think you need to do all of the counting first so you know what to print, and then print the totals.
It does not look possible to get an accurate count with the current design. Write down a series of steps to take to solve the problem and then write code to perform the steps.